With Urgot to trade you have to lane E then follow up with Q and auto attacks whilst your W (shield) is activated, the shield will slow them and the E provides a targeted attack for your Q. With the Rapid Fire Cannon this allows you to get into range to preform this, allowing your auto attack range to increase and with your W active your next auto will slow them from a far - putting them in range for your E/Q combo. The crit allows sustain through your masteries and the essence reaver/muramana allow for unlimited mana and 40% CDR.

I chose to do this in bot lane because with the defense from your support you are less vulnerable to fall behind in many ways, as Urgot is solid in lane and can win lane against most ADC's.